Re: [RFC v2 PATCH] reserve_mem: add support for static memory

[Sudeep Holla]

On Wed, Jul 08, 2026 at 05:37:33PM -0700, Shyam Saini wrote:
> Hi Catalin,
> 
> On 08 Jul 2026 11:00, Catalin Marinas wrote:
> > Hi Shyam,
> > 
> > Adding Lorenzo, Hanjun, Sudeep.
> > 
> > On Tue, Jun 30, 2026 at 10:09:11AM -0700, Shyam Saini wrote:
> > > Following up on this, As Mike pointed that reserve_mem is best effort
> > > reservation mechanism, so what is the recommended reliable Linux
> > > mechanism, if any, to reserve a predetermined memory range during
> > > early boot on ARM64/ACPI platforms for warm boot scenarios? KHO is
> > > one option, but I'm specifically looking for a solution that preserves
> > > the region across warm reboots.
> > 
> > If you need ramoops-like support, I think ACPI ERST is a better fit and
> > we don't need any memory reservation tricks. I'll let the arm ACPI
> > maintainers comment further.
> > 
> 
> while this patch mentions use case of ramoops, there are other uses cases that
> requires predetermined memory reservation at boot time, one of them is PMEM.
> Like Mike pointed out in this [1] thread, we don't seem to have an
> equivalent mechanism for reserving predetermined memory on ARM/ACPI
> platforms, as is available on ARM/DTS based platforms.
> 

Indeed, it was been discussed in several forums in the past but AFAIK there
is no conclusion or a direction towards solving this yet.

-- 
Regards,
Sudeep